When Monk holds the check up to his eyes, his watch switches from being visible to being not visible multiple times between shots.
When Mr. Monk leaves Murderuss' living room, Murderuss is seen dressed in jewelry. In the next shot he's telling Cpt. Stottlemeyer that Monk is now the Security Chief of the rapper. His golden necklace disappears between shots (while the grills are still in his mouth).
When Monk and Natalie are first introduced to Silent Killa, Natalie is standing behind Monk. In one angle she appears in front of Monk but then reappears back behind him in the next angle.
The sole witness in a homicide (no matter what the circumstances) would not be left in intensive care without having some form of police protection, especially after Stottlemeyer pointed out his existence to Murderuss, who is the primary suspect in Extra Large's death. In fact, this discussion would have been a good setup to catch the killer: to have police posted at the victim's hospital room.
The date on the newspaper with the story of the murder is Friday, 4 May 2007. This is wrong for two reasons, as it should have been a Sunday paper because it was supposed to be the morning after Daylight Savings Time began. In 2007, DST began on March 11.
Secretary's Day 2007 was on April 25 (Wednesday of the last full week in April). As another writer pointed out, Daylight Savings Time in 2007 was March 11 (second Sunday in March), and the newspaper is dated Friday, May 4, 2007.
When Murderuss visits Monk the first time, he shows Monk the news story of the murder in that morning's newspaper. This would have been impossible because the murder had happened just two hours before he visited Monk.